Another MkIII No start

[92ma71]

Okay guys, I just picked up an 89 Turbo Five speed Targa for 800. The guy had all kinds of crap not connected so I went through everything cleaning all grounds and making sure everything was connected.

I also reset timing per the TSRM.

The problem-
No fuel, No spark
The EBC will not power on which makes me thing the ECU is fried. I did alot of research on testing the ECU and im pretty good with electricity and Ive been searching all day.

okay so just messed with it for a few hours. The fuel pump will not turn on even with the two wires in the diagnositc connector jumped. Also the only wire getting 12 volts to the ECU is the BATT wire. The IGSW wire is not getting 12 volts either.

The key is loose to the point that I can pull the key out with it in the on position. Is this normal?

Im trying to get this car right to swap the 7m into my MK2.

If anyone can help make a simple way for me to test what I need to test. I would greatly appreciate it. Im in California visiting my dad for a couple weeks and were trying to have some fun working on some supras.

 

[92ma71]

Anyone? I feel like im so close to this? Ive done hours of research and Im really not comprehending

Just realized the the CEL does NOT come on at all when I put the key in the on position. Does this automatically mean the ECU is fried?

Also there is a red wire and yellow wire coming from main harness under intake manifold. The end of it is the same 2 wire oval end as the horn wire. It is a male wire plug. Can anyone tell me where this goes?

 

[92ma71]

So I got another ECU and still no start. I really need to figure out where this one plug goes from the main harness under the intake manifold. One wire gets power so im sure its used. Anyone in the supra community can help me out?

 

[jetjock]

I'm corn-fused. If you're good with electricity why not simply signal trace the relevant circuits using the TWED? Or is there something about the diagrams you don't understand? If so ask.

The key coming out means you need a new key...

 

[ifyouaint1sturlast]

You're missing something.

Power is making it to your ECU - which is how you arrived that your ECU is bad, right?

Perhaps it's the signal that tells the ECU that you've turned the key Personally, I think your issue is C ..

 

[jetjock]

From what he's written it looks like the ECU isn't getting +B. No MIL, no +12 to the coil packs, no fuel pump when jumped, ect. The absence of +B is likely because the main relay isn't on which in turn is because there's no power at IGSW. If I were him I'd be focusing on that. There must be +12 at IGSW for the ECU to wake itself up and turn the main relay on. BATT is only for keep-alive.

 

[92ma71]

Yes I just dont how to diagnose and figure why there is no 12 volts at IGSW. I swapped ECU's and no change. So the IGSW gives 12 volts which then engages the main relay?

 

[92ma71]

From what he's written it looks like the ECU isn't getting +B. No MIL, no +12 to the coil packs, no fuel pump when jumped, ect. The absence of +B is likely because the main relay isn't on which in turn is because there's no power at IGSW. If I were him I'd be focusing on that. There must be +12 at IGSW for the ECU to wake itself up and turn the main relay on. BATT is only for keep-alive.

I am getting 12 Volts to the Coil packs but still no spark.

 

[IBoughtASupra]

When your key is on, does the check engine light come on? If not, your ECU is not turning on and you need to make sure you are getting voltage to it. Follow the diagram posted above.

Does the fuel pump prime now that you say you have 12V at the coils?

 

[92ma71]

No the fuel pump does not prime and no CEL.

 

[IBoughtASupra]

You still are not getting your ECU to turn on Have you verified that the ECU is getting a signal to turn on?

Here is a pinout and get to work and let us know what you find. This is an 89+ Grey plug ECU pinout. The yellow plug ECU pinout is different, if you have the yellow plug ECU, use the second pinout.

 

[92ma71]

Which wire turns it on?

 

[IBoughtASupra]

Read the diagram and see what you think would turn it on. The locations are dependent on the year of ECU you have but EACH LABEL does the same thing in each diagram.

 

[ifyouaint1sturlast]

From what he's written it looks like the ECU isn't getting +B. No MIL, no +12 to the coil packs, no fuel pump when jumped, ect. The absence of +B is likely because the main relay isn't on which in turn is because there's no power at IGSW. If I were him I'd be focusing on that. There must be +12 at IGSW for the ECU to wake itself up and turn the main relay on. BATT is only for keep-alive.

Isn't that what I wrote?

"the signal that tells the ECU you've turned the key" and I pointed that I think the ignition switch is the problem ..

My reasoning was that the ECU triggers the EFI relay, and the EFI relay controls everything he's lacking power.. The ECU HAS constant power, but not switched power..

 

[Nick M]

The problem-
No fuel, No spark
The EBC will not power on which makes me thing the ECU is fried. I did alot of research on testing the ECU and im pretty good with electricity and Ive been searching all day.

Your answer was already provided, or at least the direction on what to do. But I have a comment for you. I spent a good amount of time at Toyota. A bad ECU is very rare. In fact, in my years there, I saw one. Contrary to what you read on the internet.

 

[jetjock]

Isn't that what I wrote?..

I was concurring. That said it's clearly not his ignition switch.

 

[92ma71]

Isn't that what I wrote?

"the signal that tells the ECU you've turned the key" and I pointed that I think the ignition switch is the problem ..

My reasoning was that the ECU triggers the EFI relay, and the EFI relay controls everything he's lacking power.. The ECU HAS constant power, but not switched power..

Gave IGSW power and it fired up. Pretty sure the ignition switch is bad giving the fact I can pull the key out with it in the on position

 

[jetjock]

Except you'd be wrong. First find where the loss of IG2 is after the switch. Then get a new key made.

 

[Smartparts]

Gave IGSW power and it fired up. Pretty sure the ignition switch is bad giving the fact I can pull the key out with it in the on position

Mine also does this, but the switch is still good.

 

[ifyouaint1sturlast]

I was concurring. That said it's clearly not his ignition switch.

Oh, my mistake.

May I ask how you arrived at the conclusion it was the key and not the sw? I'm very curious and that's a pretty pinpoint answer